This invention relates to solar collectors, greenhouses, skylights, and any other application receiving sunlight wherein it would be desirable to no longer absorb sunlight if a particular temperature is exceeded.
Most applications in which it is desired to reflect sunlight above a given temperature have relied upon shutters or louvers, which may be automatically operated.
Some applications have employed a liquid which flooded an optical system to alter its properties, and at least one has relied upon the boiling point of the liquid to cause the transition in properties. However, these systems have used copious quantities of liquid, which requires external reservoirs, plumbing and controls, and they are complex, heavy, bulky and expensive, and would present a serious contamination problem if damaged.